Speaker
Description
First Name: Louise
Last Name: Harra
Email Address: louise.harra@pmodwrc.ch
Affiliation: PMOD/WRC & ETH Zurich
All Authors: Louise Harra, Kanya Kusano, Yingjie Zhu, Krzysztof Barczynski, Adriana De Sassi, Ioannis Kontogiannis
Abstract: The Solar Orbiter high resolution EUV imager (HRI_EUV) has observed a number of solar flares with the highest ever spatial resolution in the corona. An observation was made on 19 March 2024 when Solar Orbiter was close to perihelion at a distance of 0.45 A.U. from the Sun. The spatial resolution at this time was 310 km for a 2 pixel resolution. This high resolution allows an analysis of the smallest scale EUV structures before the flare begins. The flare reaches a GOES X-ray classification of M-class. Solar Orbiter was 3.3 degrees separation from the Earth, allowing easy comparison to datasets from other Earth orbiting instruments. It is still difficult to predict when and where exactly a flare will occur, although the flare process itself is well described by the Carmichael-Sturrock-Hirayama-Kopp-Pnueman (CSHKP) magnetic reconnection model. In this work, we compare the observations with an MHD instability model which could be responsible for the trigger of a flare. This is the double-arc instability described by Kusano et al. (2020). They have developed a flare prediction model based on this instability and we compare the locations of small-scale brightenings seen with HRI. There are indications that the largest high free-energy regions are located where small-scale brightenings are observed. These could potentially be used as a proxy of energy available within an active region for flaring.